A radiographic evaluation of the tibiofibular syndesmosis

Intraoperative contralateral view for assessing accurate syndesmosis reduction

Accurate reduction of ankle syndesmosis following injury is essential to minimize tibiofibular diastasis and optimize patient outcomes. Although several radiographic parameters have been described in the coronal plane to assist in reduction, tibiofibular diastasis following syndesmotic injury often occurs in the sagittal plane, with the fibula displacing posterior relative to the tibia. A technique using lateral fluoroscopic assessment of the uninjured contralateral ankle as a comparison and guide for accurate syndesmotic reduction is described.

A reliable method for intraoperative evaluation of syndesmotic reduction

OBJECTIVES

To determine the accuracy of a technique for intraoperative assessment of syndesmotic reduction in ankle fractures.

DESIGN

Prospective, case series.

SETTING

University hospital.

PATIENTS/PARTICIPANTS

Eighteen consecutive patients with suspected syndesmotic injuries were enrolled between 2007 and 2009. The diagnosis of syndesmotic injury was based on static ankle radiographs. The study group consisted of 12 male and 6 female patients with an average age of 32 years (range 19-56 years).

INTERVENTION

All patients had mortise and talar dome lateral fluoroscopic images obtained of the uninjured ankle in the operating room. The injured ankle underwent operative reduction and provisional fixation using the uninjured ankle radiographs as a template for comparison. An intraoperative computed tomography (CT) scan was obtained to verify the syndesmotic reduction before syndesmotic fixation. If the reduction was not anatomic, the reduction was revised using fluoroscopy and the CT repeated.

MAIN OUTCOME MEASUREMENTS

Accuracy of syndesmotic reduction performed using fluoroscopy and confirmed by intraoperative CT scan.

RESULTS

Using the technique described, intraoperative CT confirmed anatomic reduction initially in 17 of the 18 fractures. The 1 case where CT did change the course of treatment, revision of fibular fracture reduction resulted in an anatomic reduction of the syndesmosis on repeat CT.

CONCLUSIONS

Accurate evaluation of the syndesmotic reduction can be determined intraoperatively using comparison mortise and talar dome lateral fluoroscopic images. Direct visualization of the syndesmosis or CT may not be necessary to achieve an accurate reduction in these injuries.

Dynamically unstable syndesmosis injuries

Distal tibiofibular syndesmosis injuries are complex injuries that often result in extended loss of playing time for athletes. Unstable syndesmosis injuries are uniformly reduced and stabilized by numerous methods. Controversy arises from syndesmosis injuries that are stable on stress radiographs but functionally unstable with loading of the ankle during athletic activity. The authors present a case of operative fixation of a dynamically unstable syndesmosis and detail the postoperative course.

False negative rate of syndesmotic injury in pronation-external rotation stage IV ankle fractures

BACKGROUND

To investigate false negative rate in the diagnosis of diastasis on initial static anteroposterior radiograph and reliability of intraoperative external rotational stress test for detection of concealed disruption of syndesmosis in pronation external rotation (PER) stage IV (Lauge-Hansen) ankle fractures.

MATERIALS AND METHODS

We prospectively studied 34 PER stage IV ankle fractures between September 2001 and September 2008. Twenty (59%) patients show syndesmotic injury on initial anteroposterior radiographs. We performed an intraoperative external rotation stress test in other 14 patients with suspicious PER stage IV ankle fractures, which showed no defined syndesmotic injury on anteroposterior radiographs inspite of a medial malleolar fracture, an oblique fibular fracture above the syndesmosis and fracture of the posterior tubercle of the tibia.

RESULTS

All 14 fractures showed different degrees of tibiofibular clear space (TFCS) and tibiofibular overlapping (TFO) on the external rotation stress test radiograph compared to the initial plain anteroposterior radiograph. It is important to understand the fracture pattern characterstic of PER stage IV ankle fractures even though it appears normal on anteroposterior radiographs, it is to be confirmed for the concealed syndesmotic injury through a routine intraoperative external rotational stress radiograph.

Stability-based classification for ankle fracture management and the syndesmosis injury in ankle fractures due to a supination external rotation mechanism of injury

The aim of this thesis was to confirm the utility of stability-based ankle fracture classification in choosing between non-operative and operative treatment of ankle fractures, to determine how many ankle fractures are amenable to non-operative treatment, to assess the roles of the exploration and anatomical repair of the AITFL in the outcome of patients with SER ankle fractures, to establish the sensitivities, specificities and interobserver reliabilities of the hook and intraoperative stress tests for diagnosing syndesmosis instability in SER ankle fractures, and to determine whether transfixation of unstable syndesmosis is necessary in SER ankle fractures. The utility of stability based fracture classification to choose between non-operative and operative treatment was assessed in a retrospective study (1) of 253 ankle fractures in skeletally mature patients, 160 of whom were included in the study to obtain an epidemiological profile in a population of 130,000. Outcome was assessed after a minimum follow-up of two years. The role of AITFL repairs was assessed in a retrospective study (2) of 288 patients with Lauge-Hansen SE4 ankle fractures; the AITFL was explored and repaired in one group (n=165), and a similar operative method was used but the AITFL was not explored in another group (n=123). Outcome was measured with a minimum follow-up of two years. Interobserver reliability of clinical syndesomosis tests (study 3) and the role of syndesmosis transfixation (study 4) were assessed in a prospective study of 140 patients with Lauge-Hansen SE4 ankle fractures. The stability of the distal tibiofibular joint was evaluated by the hook and ER stress tests. Clinical tests were carried out by the main surgeon and assistant, separately, after which a 7.5-Nm standardized ER stress test for both ankles was performed; if it was positive, the patient was randomized to either syndesmosis transfixation (13 patients) or no fixation (11 patients) treatment groups. The sensitivity and specificity of both clinical tests were calculated using the standard 7.5-Nm external rotation stress test as reference. Outcome was assessed after a minimum of one year of follow-up. Olerud-Molander (OM) scoring system, RAND 36-Item Health Survey, and VAS to measure pain and function were used as outcome measures in all studies. In study 1, 85 (53%) fractures were treated operatively using the stability based fracture classification. Non-operatively treated patients reported less pain and better OM (good or excellent 89% vs. 71%) and VAS functional scores compared to operatively treated patients although they experienced more displacement of the distal fibula (0 mm 30% vs. 69%; 0-2 mm 65% vs. 25%) after treatment. No non-operatively treated patients required operative fracture fixation during follow-up. In study 2, AITFL exploration and suture lead to equal functional outcome (OM mean, 77 vs. 73) to no exploration or fixation. In study 3, the hook test had a sensitivity of 0.25 and a specificity of 0.98. The external rotation stress test had a sensitivity of 0.58 and a specificity of 0.9. Both tests had excellent interobserver reliability; the agreement was 99% for the hook test and 98% for the stress test. There was no statistically significant difference in functional scores (OM mean, 79.6 vs. 83.6) or pain between syndesmosis transfixation and no fixation groups (Study 4). Our results suggest that a simple stability-based fracture classification is useful in choosing between non-operative and operative treatment of ankle fractures; approximately half of the ankle fractures can be treated non-operatively with success. Our observations also suggest that relevant syndesmosis injuries are rare in ankle fractures due to an SER mechanism of injury. According to our research, syndesmotic repair or fixation in SER ankle fracture has no influence on functional outcome or pain after minimum one year compared with no fixation.

Radiographic evaluation of the normal distal tibiofibular syndesmosis

BACKGROUND

Diagnosis of syndesmotic injuries is primarily based upon the assessment of ankle radiographs. The purpose of our study was to redefine the radiographic relationships of the ankle syndesmosis based on a large series of normal ankle radiographs in living subjects.

METHODS

The study involved 392 patients (218 females, 174 males) with ankle radiographs without known clinical or radiographic evidence of abnormality. Eighty-three of the 392 patients had also had normal contralateral radiographs. Tibiofibular overlap and tibiofibular clear space were measured on anteroposterior (AP) and mortise radiographs. The radiographic measurements were used to calculate means, standard deviations, and intra- and interobserver reliabilities, and compare genders and side-to-side radiographs.

RESULTS

The mean overlap was 8.3 mm on the AP and 3.5 mm on the mortise while the mean clear space was 4.6 mm on the AP and 4.3 mm on the mortise view. The least amount of overlap on the AP view was 1.8 mm. On the mortise view, there was a subset of patients that had a complete lack of overlap (less than 0 mm) with the greatest gap noted to be 1.9 mm. The greatest clear space on AP was 8 mm and on the mortise was 7.6 mm. Mortise clear space was the most accurate measure when obtaining contralateral radiographs, with a mean side-to-side difference of 0.7 ± 0.7 mm.

CONCLUSION

Lack of overlap on the mortise view can represent a normal variant, which has not been definitively reported in prior investigations.

CLINICAL RELEVANCE

Our data form the basis for revised radiographic criteria to evaluate the distal tibiofibular syndesmosis which may influence clinical management of these patients.

Rehabilitation of syndesmotic (high) ankle sprains

CONTEXT

High ankle sprains are common in athletes who play contact sports. Most high ankle sprains are treated nonsurgically with a rehabilitation program.

EVIDENCE ACQUISITION

All years of PUBMED, Cochrane Database of Systematic Reviews, CINAHL PLUS, SPORTDiscuss, Google Scholar, and Web of Science were searched to August 2010, cross-referencing existing publications. Keywords included syndesmosis ankle sprain or high ankle sprain and the following terms: rehabilitation, treatment, cryotherapy, braces, orthosis, therapeutic modalities, joint mobilization, massage, pain, pain medications, TENS (ie, transcutaneous electric nerve stimulation), acupuncture, aquatic therapy, strength, neuromuscular training, perturbation training, and outcomes.

RESULTS

Level of evidence, 5. A 3-phase rehabilitation program is described. The acute phase is directed at protecting the joint while minimizing pain, inflammation, muscle weakness, and loss of motion. Most patients are treated with some form of immobilization and have weightbearing restrictions. A range of therapeutic modalities are used to minimize pain and inflammation. Gentle mobilization and resistance exercises are used to gain mobility and maintain muscle size and strength. The subacute phase is directed at normalizing range of motion, strength, and function in activities of daily living. Progressive mobilization and strengthening are hallmarks of this phase. Neuromuscular training is begun and becomes the central component of rehabilitation. The advanced training phase focuses on preparing the patient for return to sports participation. Perturbation of support surfaces, agility drills, plyometrics, and sport-specific training are central components of this phase.

CONCLUSION

The rehabilitation guidelines discussed may assist clinicians in managing syndesmotic ankle sprains.

Intraoperative three-dimensional imaging in the treatment of acute unstable syndesmotic injuries

BACKGROUND

Acute unstable syndesmotic ankle injuries are treated primarily by reduction and stabilization with a syndesmotic screw. Examination with fluoroscopy or standard radiographs may not provide reliable information about the quality of the reduction. There is evidence that intraoperative three-dimensional imaging can demonstrate a large proportion of malreductions. The aim of this study was to determine whether intraoperative three-dimensional imaging improves the detection of inadequate positioning of the distal aspect of the fibula in the tibiofibular incisura after syndesmotic screw insertion compared with the findings on standard intraoperative fluoroscopy.

METHODS

Of 2286 ankle fractures treated operatively from August 2001 to February 2011, 251 consecutive cases (11%) were identified in a retrospective chart review. All had an unstable syndesmosis and underwent syndesmosis stabilization on the basis of an intraoperative hook test. After fluoroscopy, an intraoperative three-dimensional scan was performed. The result of this scan was documented by the surgeon and analyzed retrospectively with regard to the incidence and nature of the need for intraoperative revisions.

RESULTS

The intraoperative three-dimensional scan altered the surgical outcome in eighty-two ankles (32.7%). In most ankles (seventy-seven; 30.7%), the reduction was improved, with the most common improvement being the alignment of the fibula in the tibiofibular incisura in sixty-four patients (25.5%) followed by correction of the fracture reduction in thirteen patients (5.2%). The other five alterations involved implant corrections. The most common malpositions requiring correction after insertion of a positioning screw, with or without additional fixation, were anterior displacement and internal rotation of the distal aspect of the fibula.

CONCLUSIONS

Following open reduction and internal fixation of an ankle fracture, the correct position of the syndesmosis cannot be evaluated reliably with use of conventional radiographs or intraoperative fluoroscopy. In view of the high proportion of positive findings in this study, we believe that any treatment of a syndesmotic injury should include intraoperative three-dimensional imaging or at least a postoperative computed tomography scan.

Normal tibiofibular relationships at the syndesmosis on axial CT imaging

OBJECTIVES

Computed tomography (CT) is reported to be superior to plain radiography for imaging the syndesmosis, but CT criteria differentiating normal from abnormal tibiofibular relationships do not exist. The purpose of this study was to define normal tibiofibular relationships at the syndesmosis on axial CT imaging and to report the reliability of these measurements.

METHODS

Thirty healthy volunteers underwent CT evaluation of bilateral ankles. Axial CT measurements consisted of tibiofibular clear space, tibiofibular overlap, anterior tibiofibular interval, and fibular rotation (θ(fib)). To assess reliability, 3 investigators independently made each CT measurement on 2 separate occasions.

RESULTS

Sixty ankles were included for analysis. CT measurements demonstrated excellent intrarater and interrater reliability. There was significant anatomic variability between individuals. Specifically, statistically significant gender differences were discovered in CT measurements of tibiofibular overlap and anterior tibiofibular interval. Variance between ankles of each subject was calculated. In an uninjured population, tibiofibular intervals do not vary by more than 2.3 mm, and the rotation of the fibula does not vary by more than 6.5° between ankles of the same person.

CONCLUSIONS

Measurements of tibiofibular relationships made on axial CT images are reliable. Because of significant anatomic variation between individuals, using a patient's contralateral ankle for comparison provides a precise definition of normal tibiofibular relationships. These criteria allow for the detection of subtle variations in the tibiofibular relationships indicating instability and provide a tool for postoperatively assessing the reduction of the injured syndesmosis.

Correlating MRI findings with disability in syndesmotic sprains of NFL players

BACKGROUND

Syndesmotic sprains may be a significant source of missed playing time, especially in football players. Advanced imaging is frequently used to confirm the clinical diagnosis. Our purpose was to evaluate the prognostic ability of MRI in predicting time of disability.

METHODS

Training room records from 1993 to 2007 for three National Football League teams were reviewed. Forty-three players were diagnosed with syndesmotic ankle injuries and underwent radiographs and magnetic resonance imaging. A blinded musculoskeletal radiologist interpreted all images. Players with fractures were excluded.

RESULTS

Thirty-six professional football players were included in the final analysis. Twenty-three players had a positive squeeze test which was correlated with increased missed practices (p = 0.012) and increased missed games (p ≤ 0.01). The average number of games missed was 3.3 (range, 0 to 20) and the average number of practices missed was 16.7 (range, 0 to 114). Four players had isolated injury to the anterior tibio-fibular ligament (AITFL) (MRI Grade I). Five players had injury to the AITFL and interosseous ligament (MRI Grade II). Twenty-four players sustained injury to the AITFL, interosseous ligament, and posterior inferior tibio-fibular ligament (MRI Grade III). Three players had Grade III injuries with additional injury to the deltoid ligament (MRI Grade IV). Increasing grade of injury was positively correlated with increased number of missed games (p = 0.033) and missed practices (p = 0.002).

CONCLUSION

MRI can be useful to help delineate the injury pattern and associated injuries, and may be useful in predicting time of disability using a grading system. Positive squeeze test can also be useful to determine prognosis.

Correlation between radiological assessment of acute ankle fractures and syndesmotic injury on MRI

OBJECTIVE

Owing to the shortcomings of clinical examination and radiographs, injury to the syndesmotic ligaments is often misdiagnosed. When there is no indication requiring that the fractured ankle be operated on, the syndesmosis is not tested intra-operatively, and rupture of this ligamentous complex may be missed. Subsequently the patient is not treated properly leading to chronic complaints such as instability, pain, and swelling. We evaluated three fracture classification methods and radiographic measurements with respect to syndesmotic injury.

MATERIALS AND METHODS

Prospectively the radiographs of 51 consecutive ankle fractures were classified according to Weber, AO-Müller, and Lauge-Hansen. Both the fracture type and additional measurements of the tibiofibular clear space (TFCS), tibiofibular overlap (TFO), medial clear space (MCS), and superior clear space (SCS) were used to assess syndesmotic injury. MRI, as standard of reference, was performed to evaluate the integrity of the distal tibiofibular syndesmosis. The sensitivity and specificity for detection of syndesmotic injury with radiography were compared to MRI.

RESULTS

The Weber and AO-Müller fracture classification system, in combination with additional measurements, detected syndesmotic injury with a sensitivity of 47% and a specificity of 100%, and Lauge-Hansen with both a sensitivity and a specificity of 92%. TFCS and TFO did not correlate with syndesmotic injury, and a widened MCS did not correlate with deltoid ligament injury.

CONCLUSION

Syndesmotic injury as predicted by the Lauge-Hansen fracture classification correlated well with MRI findings. With MRI the extent of syndesmotic injury and therefore fracture stage can be assessed more accurately compared to radiographs.

Comparison of magnetic resonance imaging to physical examination for syndesmotic injury after lateral ankle sprain

BACKGROUND

Clinical assessment of syndesmotic injury usually consists of two tests: the ankle external rotation test and squeeze test. This study sought to determine the sensitivity and specificity of both for syndesmotic injury secondary to lateral ankle sprain.

METHODS

Fifty-six patients with sprained ankles underwent clinical examination for syndesmotic injury with the aforementioned tests. Clinical findings were compared against magnetic resonance imaging (MRI) of the ankle. Sprains were graded on anatomical and functional classification scales, and correlation and agreement between both scales were assessed.

RESULTS

The MRI prevalence of syndesmotic injury in patients with lateral ankle sprains was 17.8%. Sensitivity and specificity were 30% and 93.5% for the squeeze test, and 20% and 84.8% for the external rotation test, respectively. Using the anatomical scale for sprain grading, 40% of syndesmotic injuries occurred in Grade I, 40% in Grade II, and 20% in Grade III sprains. Ten percent of patients with syndesmotic injury had no lateral ligament injury on MRI, 70% had injury of the anterior talofibular (ATFL) ligament, and 20% had injury to the ATFL and calcaneofibular (CFL).

CONCLUSION

The sensitivity of the squeeze test and external rotation test was low, suggesting that physical examination often fails to diagnose syndesmotic injury. Conversely, specificity was very high; nearly all patients with a positive test actually had syndesmotic injury. Severity of ankle sprain was not associated with prevalence of syndesmotic injury.

Dislocation of the proximal and distal tibiofibular syndesmotic complex without associated fracture: case report

Level of Evidence: V, Expert Opinion

Limitations of standard fluoroscopy in detecting rotational malreduction of the syndesmosis in an ankle fracture model

BACKGROUND

When treating ankle fractures with associated syndesmosis injury, failure to anatomically reduce the syndesmosis may lead to poor outcome. While shortening and posterior subluxation of the distal fibula are readily detected by intraoperative fluoroscopy, it is unclear how well malrotation can be assessed. The ability of fluoroscopy to detect rotational malreduction of the fibula was the subject of this study.

MATERIALS AND METHODS

Distal fibula fractures with complete syndesmotic injury were produced in ten cadaveric ankles. Two Kirschner wires were used to fix the fibula in neutral (0 degrees), 10 to 30 degrees of external rotation (ER), and 10 degrees to 30 degrees of internal rotation (IR). Using C-arm fluoroscopy tibio-fibular clear space and tibio-fibular overlap in the AP and mortise views, and posterior fibular subluxation in the lateral view were measured to assess reduction of the syndesmosis.

RESULTS

The radiographic indices were able to detect as little as 10 degrees of IR but were within their normal range in up to 30 degrees of ER. When assessing for a 2mm difference compared to the intact ankle, sensitivity of all indices were low after more than 15 degrees ER, but high and clinically useful after more than 15 degrees of IR.

CONCLUSION

Radiographic indices for syndesmosis disruption could not detect ER malreduction of the syndesmosis of up to 30 degrees.

CLINICAL RELEVANCE

In the setting of ankle fractures with syndesmosis disruption, fixing the fibula in as much as 30 degrees of external rotation may go undetected using intraoperative fluoroscopy alone.

The radiographic fate of the syndesmosis after trans-syndesmotic screw removal in displaced ankle fractures

The purpose of this study was to evaluate the radiographic changes of the tibiofibular position and the ankle mortise after removal of trans-syndesmotic fixation to determine if there is loss or maintenance of correction. In addition, the effect of the type of rotational injury, early weight bearing, and the number of trans-syndesmotic screws used on the integrity of the inferior tibiofibular articulation or ankle mortise after screw removal were evaluated. An analysis was conducted of 86 patients, with an unstable rotational ankle fracture requiring open reduction with syndesmosis screw stabilization. Routine radiographic parameters were measured just after open reduction and just before syndesmotic screw removal. There was a high correlation of loss of the integrity of the syndesmotic parameters after screw removal. However, the medial clear space of the ankle changed an insignificant amount, suggesting that although there appears to be some loss of maintenance, the talus did not shift laterally at the expense of a mobile syndesmosis. Ankle injuries requiring stabilization of syndesmotic instability with use of temporary trans-syndesmotic fixation achieve a stable ankle mortise after removal. Tibiofibular diastasis is commonplace upon removal of the syndesmotic hardware, but the ankle mortise remains unchanged. Based on the radiographic criteria described in this study, the postoperative change in medial clear space or tibiofibular diastasis has no bearing on fracture type, deltoid injury, or the use of 1 or 2 cortical screws. As such, other unknown mechanisms affecting the integrity of the syndesmosis after screw removal are in place.

Anatomy of the distal tibiofibular syndesmosis in adults: a pictorial essay with a multimodality approach

A syndesmosis is defined as a fibrous joint in which two adjacent bones are linked by a strong membrane or ligaments.This definition also applies for the distal tibiofibular syndesmosis, which is a syndesmotic joint formed by two bones and four ligaments. The distal tibia and fibula form the osseous part of the syndesmosis and are linked by the distal anterior tibiofibular ligament, the distal posterior tibiofibular ligament, the transverse ligament and the interosseous ligament. Although the syndesmosis is a joint, in the literature the term syndesmotic injury is used to describe injury of the syndesmotic ligaments. In an estimated 1–11% of all ankle sprains, injury of the distal tibiofibular syndesmosis occurs. Forty percent of patients still have complaints of ankle instability 6 months after an ankle sprain. This could be due to widening of the ankle mortise as a result of increased length of the syndesmotic ligaments after acute ankle sprain. As widening of the ankle mortise by 1 mm decreases the contact area of the tibiotalar joint by 42%, this could lead to instability and hence early osteoarthritis of the tibiotalar joint. In fractures of the ankle, syndesmotic injury occurs in about 50% of type Weber B and in all of type Weber C fractures. However,in discussing syndesmotic injury, it seems the exact proximal and distal boundaries of the distal tibiofibular syndesmosis are not well defined. There is no clear statement in the Ashhurst and Bromer etiological, the Lauge-Hansen genetic or the Danis-Weber topographical fracture classification about the exact extent of the syndesmosis. This joint is also not clearly defined in anatomical textbooks, such as Lanz and Wachsmuth. Kelikian and Kelikian postulate that the distal tibiofibular joint begins at the level of origin of the tibiofibular ligaments from the tibia and ends where these ligaments insert into the fibular malleolus. As the syndesmosis of the ankle plays an important role in the stability of the talocrural joint, understanding of the exact anatomy of both the osseous and ligamentous structures is essential in interpreting plain radiographs, CT and MR images, in ankle arthroscopy and in therapeutic management. With this pictorial essay we try to fill the hiatus in anatomic knowledge and provide a detailed anatomic description of the syndesmotic bones with the incisura fibularis, the syndesmotic recess, synovial fold and tibiofibular contact zone and the four syndesmotic ligaments. Each section describes a separate syndesmotic structure, followed by its clinical relevance and discussion of remaining questions.

Management of chronic disruption of the distal tibiofibular syndesmosis

Disruption of the distal tibiofibular syndesmosis is frequently accompanied by rotational ankle fracture such as pronation-external rotation and rarely occurs without ankle fracture. In such injury, not only inadequately treated or misdiagnosed cases, but also correctly diagnosed cases can possibly result in a chronic pattern which is more troublesome to treat than an acute pattern. This paper reviews anatomical and biomechanical characteristics of the distal tibiofibular joint, the mechanism of chronic disruption of the distal tibiofibular syndesmosis, radiological and arthroscopic diagnosis, and surgical treatment.

Salvage of chronic instability of the syndesmosis with distal tibiofibular arthrodesis: functional and radiographic results

BACKGROUND

Failure to treat an injury of the syndesmosis after an ankle fracture can lead to a poor functional outcome and posttraumatic arthritis. The results after reconstruction of an ankle with an incongruous mortise, chronic diastasis of the syndesmosis, and arthritis remain unknown. The purpose of the present study was to review the radiographic and clinical results of salvaging this condition through reduction and arthrodesis of the distal tibiofibular articulation.

METHODS

Ten patients (mean age, fifty-four years) with chronic syndesmotic instability who underwent salvage by a single surgeon were evaluated retrospectively. Five parameters of mortise and syndesmotic alignment were measured on weight-bearing radiographs that were made preoperatively and at the time of the latest follow-up. The extent of arthritis in the ankle was graded with use of an established classification system. Clinical rating scores that were recorded preoperatively and at the time of the latest follow-up were culled from the medical records and were compared. Each patient's stated satisfaction with the operation and willingness to undergo the operation again were retrieved from the medical records.

RESULTS

After a mean duration of follow-up of forty-one months (minimum, two years), the medial clear space, talocrural angle, and talar tilt had improved. No ankle demonstrated progression of arthritis on the basis of the radiographic grade. The clinical rating score improved significantly because of improvements in the pain, activity, maximum walking distance, and gait subscales. Two patients had a total of three additional procedures. Both had prominent implants removed, and one subsequently underwent an ankle arthroscopy. All patients reported satisfaction with and a willingness to undergo the procedure again. At the time of the latest follow-up, no patient had undergone an ankle arthrodesis.

CONCLUSIONS

The significant improvements in the radiographic and functional measures of outcome that were observed in this small cohort suggest that chronic syndesmotic instability after ankle fracture can be salvaged with reduction and arthrodesis of the distal tibiofibular articulation. Furthermore, the reconstruction of an incongruous and arthritic ankle is an alternative to and may postpone the subsequent need for ankle arthrodesis or arthroplasty.

New technology and techniques in the treatment of foot and ankle injuries

The advancement of new technologies in the treatment of foot and ankle injuries seems exponential over the last several years. As surgeons expand their knowledge of the pathology and improve their treatment techniques, they come upon new and different ways to treat the same pathologic conditions. Foot and ankle injuries are commonplace in competitive sports. This article provides an overview of the diagnosis and treatment, including surgical techniques, of common foot and ankle injuries.

Management of common sports-related injuries about the foot and ankle

Foot and ankle injuries are commonplace in competitive sports. Improvements in injury surveillance programs and injury reporting have enabled physicians to better recognize and manage specific foot and ankle injuries, with a primary goal of efficient and safe return to play. Athletes are becoming stronger, faster, and better conditioned, and higher-energy injuries are becoming increasingly common. Close attention is required during examination to accurately identify such injuries as turf toe, ankle injuries, tarsometatarsal (ie, Lisfranc) injuries, and stress fractures. Early diagnosis and management of these injuries are critical. Ultimately, however, pressure to return to play must not compromise appropriate care and long-term outcomes.

[Fractures of the upper ankle]

Upper ankle injuries are the most common reason for presentation in emergency departments. The initial treatment is often left in the hands of young clinical professionals. While the mechanism of injury might appear banal, insufficient diagnosis and treatment can lead to long periods of disability and functional impairment of the joint. Therefore, it is the aim of this work to provide a thorough understanding of the anatomy, biomechanics, mechanism of injury, diagnostic and operative procedures of ankle joint fractures.

Management of ankle syndesmosis injuries in the athlete

Syndesmotic injuries or high ankle sprains in athletes can occur in elite and recreational athletes. They typically require a longer recovery and a significant delay in return to play compared with routine ankle sprains. Avoiding a misdiagnosis is important and is dependent on being aware of the mechanism of injury, a thorough physical examination, and careful interpretation of imaging studies. Management is guided by the severity of injury and the demands of the athlete. Many mild or stable injuries can be treated nonoperatively; however, acute surgical repair or stabilization in high-grade injuries can provide excellent results and an earlier return to play in selected cases.

Tibial shaft fracture with concomitant syndesmotic injury: a case report

Level of Evidence: V, Expert Opinion

Comparison of two intraoperative assessment methods for injuries to the ankle syndesmosis. A cadaveric study

BACKGROUND

Intraoperative stress testing is required for the detection of syndesmosis instability following an ankle fracture. The present study compared two stress tests for the detection of syndesmotic injury.

METHODS

A true mortise radiograph of the ankle was made for fourteen cadaver joints. Specimens were randomized into two groups to simulate ligament and syndesmosis injury on the basis of the Danis-Weber classification system. In the first group, the anterior inferior tibiofibular ligament was divided first (Weber B(r)), followed sequentially by division of the interosseous membrane (Weber C) and the deltoid ligament. In the second group, the deltoid ligament was divided first, followed by the anterior inferior tibiofibular ligament. Radiographs were made at each stage with use of two methods of stressing the ankle mortise: (1) external rotation of the foot with an external moment of 7.5 Nm, and (2) application of a lateral force of 100 N. Tibiofibular overlap, tibiofibular clear space, and medial clear space were measured.

RESULTS

Lateral stress produced a significantly greater increase in the tibiofibular clear space than did the external rotation test for Weber C injuries and Weber C plus deltoid ligament injuries. A greater increase in the tibiofibular clear space was noted during the lateral stress test when both the deltoid and the anterior inferior tibiofibular ligament had been sectioned (p < 0.05). The external rotation stress test produced a significant increase in the medial clear space in the presence of isolated anterior inferior tibiofibular ligament and deltoid ligament injuries (p < 0.05).

CONCLUSIONS

For the detection of syndesmotic instability at the site of ankle fractures on stress radiographs, the lateral stress test appeared to be superior to the external rotation stress test in this cadaver model.

Delayed operative treatment of syndesmotic instability. Current concepts review

OBJECTIVE

To review the literature concerning articles evaluating the delayed operative treatment of isolated syndesmotic instability.

MATERIAL AND METHODS

The main databases Pubmed/Medline, Cochrane Database of Systematic Reviews, Cochrane Clinical Trial Register, Current Controlled Trials and Embase were searched from 1988 to September 2008 to identify studies relating to the late reconstruction of the distal tibiofibular syndesmosis after isolated syndesmotic injury. The level of evidence of the included articles was scored.

RESULTS

Fifteen articles were identified, involving 94 ankles with a delayed reconstruction for isolated syndesmotic instability.

CONCLUSION

In subacute (6 weeks to 6 months) total ruptures the focus is to restore the normal anatomy by repair of the ruptured ligament with placement of a syndesmotic screw. On base of the literature in combination with experience in clinical practice some guidelines are formulated. If inadequate remnants of the anterior inferior tibiofibular ligament (AITFL) are present, a tendon graft can be used. The insertion of the AITFL on the tibia can be medialised with a bone block and fixed with a screw. For the treatment of persistent widening and late instability these reconstruction techniques have to be used combined with debridement and placement of a syndesmotic screw to protect the reconstruction. Most adequate treatment for chronic syndesmotic instability (>6 months) is the creation of a synostosis to stabilise the distal tibiofibular joint. Late repairs give satisfactory but less favourable outcome as compared to properly treated acute injuries. It is not easy to regain complete stability by means of these secondary procedures.

Bolt fixation for syndesmotic injuries

We performed a retrospective study of 28 patients who underwent bolt fixation for a syndesmotic injury to the ankle. The mean follow-up period was 66 months (range: 24-139 months). The results of surgery were assessed clinically and radiographically. Overall, this fixation device was found to adequately stabilise the syndesmosis during healing. Radiologically accurate syndesmosis reduction was achieved in 26 patients. The mean AOFAS score was 86 (range: 33-100). The majority of patients were very satisfied with the overall result. It is a simple and quick operative procedure providing reliable syndesmotic reduction. The material should not be removed prior to walking. The only drawback is the greater need for removal in the event of local symptoms.

Transosseous fixation of the distal tibiofibular syndesmosis: comparison of an interosseous suture and endobutton to traditional screw fixation in 50 cases

In this prospective cohort study, we compared screw fixation to interosseous suture with endobutton repair of the syndesmosis. Outcomes of interest included preoperative and postoperative modified American Orthopedic Foot and Ankle Society (AOFAS) hindfoot and ankle scores, and Short Form-12 health status scores, as well as radiographic measurements and the time to full weight bearing. Mean averages and ranges were calculated for numeric variables, and outcomes for each fixation group were compared statistically with Student t test. The cohort consisted of 50 patients; 25 in the screw fixation group and 25 in the interosseous wire with endobuttons group. The mean patient age was 34.68 (15 to 55) years in the interosseous suture endobutton group and 36.68 (17 to 74) years in the screw group, and the mean follow-up was 10.78 (range 6 to 12) months in the interosseous suture endobutton group, and 8.20 (range 4 to 24) months in the screw group. No statistically significant differences (P < or = .05) were noted in regard to age, follow-up duration, time to postoperative weight bearing, or subjective outcome scores between the fixation groups; although statistically significant improvements were noted in the subjective scores for each fixation group between the preoperative and postoperative measurements. The results of this study indicate that the interosseous suture with endobuttons is a reasonable option for repair of ankle syndesmotic injuries, and may be as effective as traditional internal screw fixation.

LEVEL OF CLINICAL EVIDENCE

2.

Stress radiographs in orthopaedic surgery

Stress radiographs are useful in determining the amount of ligamentous laxity present following trauma. The results may be helpful in determining diagnosis, surgical indications, and the type and timing of rehabilitation. Some techniques for obtaining stress radiographs involve specific patient positioning or manually applied force; others require use of a particular testing device. Stress radiographs may be obtained for a variety of anatomic areas and joints. The parameters that define abnormality on stress radiographs should be compared with those of clinical findings. The use of common and novel methods to obtain stress radiographs has led to improved identification and diagnosis of many orthopaedic pathologies. Some of these techniques have been developed with the aim of reducing patient discomfort or minimizing the clinician's exposure to radiation.

Injuries to the distal tibiofibular syndesmosis: an evidence-based approach to acute and chronic lesions

Injuries to the distal tibiofibular syndesmosis are frequent in collision sports. Most of these injuries are not associated with latent or frank diastasis between the distal tibia and fibula and are treated as high ankle sprains, with an extended protocol of physical therapy. Relevant instability of the syndesmosis results from rupture of two or more ligaments leading to a diastasis of more than 2 mm and requiring surgical fixation. Most of these syndesmosis ruptures are associated with bony avulsions or malleolar fractures. Treatment consists of anatomic reduction of the fibula and fixation with one or two tibiofibular syndesmosis screws. Proper reduction and positioning of the screws are more predictive of a good clinical result than the material, size, and number of cortices purchased. Chronic injuries without instability are treated by arthroscopic or open debridement and arthrolysis. Chronic syndesmotic instability can be treated with a three-strand peroneus longus ligamentoplasty in the absence of symptomatic arthritis or bony defects.

Injuries to the tibiofibular syndesmosis

The management of injury to the distal tibiofibular syndesmosis remains controversial in the treatment of ankle fractures. Operative fixation usually involves the insertion of a metallic diastasis screw. There are a variety of options for the position and characterisation of the screw, the type of cortical fixation, and whether the screw should be removed prior to weight-bearing. This paper reviews the relevant anatomy, the clinical and radiological diagnosis and the mechanism of trauma and alternative methods of treatment for injuries to the syndesmosis.

Arthroscopy-assisted repair of latent syndesmotic instability of the ankle

PURPOSE

The purpose of this study was to investigate the results of repair of latent ankle syndesmotic instability and widening by an arthroscopic and percutaneous approach.

METHODS

This case study series presents 6 patients who presented with latent syndesmotic instability after sustaining a rotational ankle injury. All 6 patients underwent arthroscopy-assisted repair and percutaneous fixation of the disrupted ankle mortise. Objective radiographic findings were obtained pre- and postoperatively as well as subjective patient outcomes using American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score.

RESULTS

After a minimum of 2 years of follow-up, all patients had improvement of their AOFAS scores with a mean change of 32 (standard deviation, 7.0; P = .0001). The function component of the AOFAS score had the largest change from preoperative to postoperative status, with a value of 15 (P = .0009). Radiographic parameters were improved in all 6 patients. The reduction of the medial clear space was the most consistent finding, with a postoperative medial clear space ranging from 2.6 to 3.5 mm (mean change, 3.2 mm; P = .0002).

CONCLUSIONS

Our small series, with a minimum follow-up of 24 months, suggests that arthroscopy-assisted treatment of latent syndesmotic instability is an effective method. The primary outcome measure of AOFAS scores showed statistically significant improvement in pain and function at final follow-up. Alignment of the ankle did not exhibit statistically significant changes. Both of the secondary radiographic outcome measures were statistically improved at final follow-up.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Treatment of syndesmotic disruptions with the Arthrex Tightrope: a report of 25 cases

BACKGROUND

The complexity of syndesmotic injuries, often with both bone and soft tissue injury mandates an expeditious diagnosis and treatment to avoid unfavorable long term outcomes. Various methods of fixation of the syndesmosis have been reported. We present the largest series evaluating the Arthrex Tightrope for management of syndesmotic injuries.

MATERIALS AND METHODS

Twenty-five patients with disruption of the distal tibiofibular articulation underwent treatment with an Arthrex Tightrope. In 21 cases, a single tightrope was placed, and in four cases, two tightropes were utilized. Associated ankle fractures were treated using proper AO technique. Those patients with diabetes and/or neuroarthropathic changes foot or ankle were not included in this study. Postoperative evaluation parameters included radiographic measurements, a modified AOFAS scoring system and SF-12.

RESULTS

Average followup was 10.8 months. The mean time to full weightbearing was 5.5 (range, 2 to 8) weeks. Postoperative radiographic analysis of the mean distance from the tibial plafond to the placement of the tightrope(s), medial clear space, average postoperative tibiofibular overlap and the mean tibiofibular clear space demonstrated no evidence of re-displacement of the syndesmotic complex at an average of 10.8 (range, 6 to 12) months. The modified AOFAS hindfoot scoring scale and SF-12 both demonstrated significant improvements; preoperative values were assessed in the office with the first patient visit as they are incorporated into the patient intake form that each patient fills out at the initial visit.

CONCLUSION

Utilization of the tightrope in diastasis of the syndesmosis should be considered as a good option. The method of placement is quick, can be minimally invasive, and obviates the need for hardware removal. In this series, it maintained excellent reduction of the syndesmosis.

Which ankle fractures require syndesmotic stabilization?

Syndesmotic ruptures associated with ankle fractures are most commonly caused by external rotation of the foot, eversion of the talus within the ankle mortise, and excessive dorsiflexion. The distal tibiofibular syndesmosis consists of the anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, and interosseous ligament, and it is essential for stability of the ankle mortise. Despite the numerous biomechanical and clinical studies pertaining to ankle fractures, there are no uniform recommendations regarding the use of the syndesmotic screw for specific injury patterns and fracture types. The objective of this review was to formulate recommendations for clinical practice related to the use of syndesmotic screw placement.

Syndesmotic ankle sprains in athletes

Ankle sprains are among the most common athletic injuries and represent a significant source of persistent pain and disability. Despite the high incidence of ankle sprains in athletes, syndesmosis injuries have historically been underdiagnosed, and assessment in terms of severity and optimal treatment has not been determined. More recently, a heightened awareness in sports medicine has resulted in more frequent diagnoses of syndesmosis injuries. However, there is a low level of evidence and a paucity of literature on this topic compared with lateral ankle sprains. As a result, no clear guidelines are available to help the clinician assess the severity of injury, choose an imaging modality to visualize the injury, make a decision in terms of operative versus nonoperative treatment, or decide when the athlete may return to play. Increased knowledge and understanding of these injuries by clinicians and researchers are essential to improve the prevention, diagnosis, and treatment of this significant condition. This review will discuss the anatomy, mechanism of injury, diagnosis, and treatment of syndesmosis sprains of the ankle while identifying controversies in management and topics for future research.

Ankle syndesmotic injury

Ankle syndesmotic injury does not necessarily lead to ankle instability; however, the coexistence of deltoid ligament injury critically destabilizes the ankle joint. Syndesmotic injury may occur in isolation or may be associated with ankle fracture. In the absence of fracture, physical examination findings suggestive of injury include ankle tenderness over the anterior aspect of the syndesmosis and a positive squeeze or external rotation test. Radiographic findings usually include increased tibiofibular clear space decreased tibiofibular overlap, and increased medial clear space. However, syndesmotic injury may not be apparent radiographically; thus, routine stress testing is necessary for detecting syndesmotic instability. The goals of management are to restore and maintain the normal tibiofibular relationship to allow for healing of the ligamentous structures of the syndesmosis. Fixation of the syndesmosis is indicated when evidence of a diastasis is present. This may be detected preoperatively, in the absence of fracture, or intraoperatively, after rigid fixation of the medial malleolus and fibula fractures. Failure to diagnose and stabilize syndesmotic disruption adversely affects outcome.

Chronic tibiofibular syndesmosis injury of ankle: evaluation with contrast-enhanced fat-suppressed 3D fast spoiled gradient-recalled acquisition in the steady state MR imaging

PURPOSE

To retrospectively determine the accuracy of coronal contrast material-enhanced fat-suppressed three-dimensional (3D) fast spoiled gradient-recalled acquisition in the steady state (SPGR) magnetic resonance (MR) imaging, as compared with that of routine transverse MR imaging, in the assessment of distal tibiofibular syndesmosis injury, with arthroscopy as the reference standard.

MATERIALS AND METHODS

The review board of the College of Medicine in Yonsei University approved this study; informed consent was waived. The study group comprised 45 patients (26 men, 19 women; mean age, 32.1 years; range, 18-58 years) with a chronic ankle injury who had undergone MR imaging and arthroscopic surgery. Three independent readers retrospectively reviewed the two sets of MR images (one set of gadolinium-enhanced 3D fast SPGR images and one set of routine T1-, T2-, and intermediate-weighted images). Scores from 1 to 5 in increasing order of the probability of injury were assigned to both sets. Arthroscopy was the reference standard. Syndesmotic recess height was measured on contrast-enhanced images. The two sets of images were compared for diagnostic performance with receiver operating characteristic (ROC) analysis. Dissection and histologic examination of six cadaveric ankles was performed to assess the syndesmotic area and ascertain the enhancing structure at MR imaging.

RESULTS

At arthroscopy, syndesmotic injury was found in 24 ankles but not in 21 ankles. Areas under the ROC curve were significantly higher for the contrast-enhanced images (P<.05). The contrast-enhanced set showed higher accuracy, sensitivity, and specificity compared with the routine set for the assessment of syndesmosis injury. Mean syndesmotic recess height was significantly greater (P<.05) in patients with syndesmotic injury. Dissection and histologic examination revealed a highly vascular synovial fold in the syndesmotic area that is expected to enhance at MR imaging.

CONCLUSION

In the assessment of chronic syndesmosis injury, coronal gadolinium-enhanced fat-suppressed 3D fast SPGR MR images were more sensitive, specific, and accurate than routine MR images.

Evidence-based approach to treatment of acute traumatic syndesmosis (high ankle) sprains

Ankle sprains in the athlete are one of the most common injuries, and syndesmosis or "high-ankle" sprains seem to being diagnosed at an increasing rate. As a result, there has been a heightened interest in recognizing and treating these difficult injuries on a timely basis, particularly in the athlete. Although the recognition and diagnosis of these injuries have improved, there still exists a paucity of information on optimal conservative and operative management. In this paper, a systematic review of the literature was conducted to provide an evidence-based rationale in the diagnosis and treatment of syndesmosis (high ankle) sprains in athletes. It is obvious from the low level of evidence available in the literature on this topic that a great deal of work is needed before conclusive statements regarding the management of these injuries can be made with confidence. The current diagnostic tests are not very specific. Because this is a spectrum of injury, there is a lot of variability in the time lost from sport. It is clear that we need a much more definitive diagnostic process for this injury that allows us to predict the severity of the injury, time loss from sport, and the treatment required.

Three-dimensional volume rendering of tibiofibular joint space and quantitative analysis of change in volume due to tibiofibular syndesmosis diastases

OBJECTIVE

The diagnosis of ankle syndesmosis injuries is made by various imaging techniques. The present study was undertaken to examine whether the three-dimensional reconstruction of axial CT images and calculation of the volume of tibiofibular joint space enhances the sensitivity of diastases diagnoses or not.

DESIGN

Six adult cadaveric ankle specimens were used for spiral CT-scan assessment of tibiofibular syndesmosis. After the specimens were dissected, external fixation was performed and diastases of 1, 2, and 3 mm was simulated by a precalibrated device. Helical CT scans were obtained with 1.0-mm slice thickness. The data was transferred to the computer software AcquariusNET. Then the contours of the tibiofibular syndesmosis joint space were outlined on each axial CT slice and the collection of these slices were stacked using the computer software AutoCAD 2005, according to the spatial arrangement and geometrical coordinates between each slice, to produce a three-dimensional reconstruction of the joint space. The area of each slice and the volume of the entire tibiofibular joint space were calculated. The tibiofibular joint space at the 10th-mm slice level was also measured on axial CT scan images at normal, 1, 2 and 3-mm joint space diastases.

RESULTS

The three-dimensional volume-rendering of the tibiofibular syndesmosis joint space from the spiral CT data demonstrated the shape of the joint space and has been found to be a sensitive method for calculating joint space volume. We found that, from normal to 1 mm, a 1-mm diastasis increases approximately 43% of the joint space volume, while from 1 to 3 mm, there is about a 20% increase for each 1-mm increase.

CONCLUSIONS

Volume calculation using this method can be performed in cases of syndesmotic instability after ankle injuries and for preoperative and postoperative evaluation of the integrity of the tibiofibular syndesmosis.

Malreduction of the tibiofibular syndesmosis in ankle fractures

BACKGROUND

Diagnosis and reduction of syndesmosis injuries in ankle fractures can be challenging. Previous studies have demonstrated that standard radiographic measurements used to evaluate the integrity of the syndesmosis are inaccurate. The purpose of this study was to determine the adequacy of standard postoperative radiographic measurements in assessing syndesmotic reduction compared to CT and to determine the prevalence of postoperative syndesmotic malreduction in a patient cohort.

METHODS

Twenty-five patients with ankle fractures and syndesmotic instability who had open reduction and syndesmotic fixation were evaluated. All patients had a standard radiographic series postoperatively followed by a CT scan. Radiographic measurements were made by three observers to determine the tibiofibular relationship. Axial CT scan images were judged for quality of reduction of the syndesmosis by measuring the distance between the fibula and the anterior and posterior facets of the incisura. Differences between the anterior and posterior measurements of more than 2 mm were considered incongruous.

RESULTS

Six patients (24%) had evidence of postoperative diastasis using the radiographic criteria, four of whom had evidence of malreduction on postoperative CT scan. Conversely, 13 patients (52%) had incongruity of the fibula within the incisura on CT scan (average 3.6 mm, range 2.0 to 8.0 mm), only four of whom had one or more abnormal radiographic measurements. In 10 (77%) of the 13 malreductions seen on CT scan, the posterior measurement was greater, indicating that internal rotation or anterior translation of the fibula may have occurred. Sensitivity of radiographs was 31% and the specificity was 83% compared to CT.

CONCLUSIONS

Many syndesmoses were malreduced on CT scan but went undetected by plain radiographs. Radiographic measurements did not accurately reflect the status of the distal tibiofibular joint in this series of ankle fractures. Furthermore, postreduction radiographic measurements were inaccurate for assessing the quality of the reduction. Although we did not seek to correlate functional outcomes, the known morbidity of postoperative syndesmotic malreduction should lead to heightened vigilance for assessing accurate syndesmosis reduction intraoperatively.

Acute and chronic syndesmosis injuries: pathomechanisms, diagnosis and management

Both acute and chronic syndesmotic injuries can lead to significant morbidity. The key to management of acute injuries is anatomic reduction of the fibula and the syndesmosis. A high index of suspicion for syndesmotic injuries will allow the surgeon to avoid the difficult reconstruction options for chronic diastasis.

Ankle syndesmosis injuries: anatomy, biomechanics, mechanism of injury, and clinical guidelines for diagnosis and intervention

Syndesmosis injuries are rare, but very debilitating and frequently misdiagnosed. The purpose of this clinical commentary is to review the mechanisms of syndesmotic injuries, clinical examination methods, diagnosis, and management of the injuries. Cadaveric studies of the syndesmosis and deltoid ligaments are also reviewed for further understanding of stress transmission and the roles of different structures in stabilizing the distal syndesmosis. External rotation and excessive dorsiflexion of the foot on the leg have been reported as the most common mechanisms of injury. The injury is most often incurred by individuals who participate in skiing, football, soccer, and other sport activities played on turf. The external rotation and squeeze tests are reliable tests to detect this injury. The ability of imaging studies to assist in an accurate diagnosis may depend on the severity of the injury. The results of cadaveric studies indicate the importance of the deltoid ligament in maintaining stability of the distal tibiofibular syndesmosis and the congruency of the ankle mortise. Intervention programs with early rigid immobilization and pain relief strategies, followed by strengthening and balance training are recommended. Heel lift and posterior splint intervention can be used to avoid separation of the distal syndesmosis induced by excessive dorsiflexion of the ankle joint. Application of a rigid external device should be used with caution to prevent medial-lateral compression of the leg superior to the ankle mortise, thereby inducing separation of the distal syndesmosis articulation. Surgical intervention is an option when a complete tear of the syndesmotic ligaments is present or when fractures are observed.

Anatomical evaluation and clinical importance of the tibiofibular syndesmosis ligaments

The aim of this study was to describe the detailed anatomical arrangement of ligaments of the tibiofibular syndesmosis and to highlight the clinical aspects of fracture dislocations. This study was performed on 42 legs of adult human embalmed cadavers. Tibiofibular syndesmosis ligaments attachments and their mutual relationships were described and their dimensions were measured. The anterior tibiofibular ligament is usually composed of three parts. This ligament runs obliquely at laterodistaly direction making 35 degrees angle with horizontal plane and posteriorly 65 degrees angle with sagittal plane. The posterior tibiofibular ligament runs almost horizontally 20 degrees angle with horizontal plane. The mean thicknesses of tibial and fibular attachments are 6.38+/-1.91 mm and 9.67+/-1.74 mm, respectively. The inferior transverse ligament originates from just below the posterior tibiofibular ligament, which has variations on the shape and dimensions due to its attachment points. The average length is 36.60+/-9.51 mm. The network between the fibular notch and the distal fibula has been filled with the interosseous tibiofibular ligament whose fibers follow the laterodistal and anterior direction from the tibia to the fibula. It lies proximally 30-40 mm from the mortise. At the inferior view of the tibiofibular syndesmosis a pyramidal shaped cartilaginous facet was observed which was attached to the fibula. The length of this cartilage was variable. Some of synovial plicas from the ankle joints synovial membrane were observed at this view. We conclude that the results of this study may be useful to both orthopedic surgeons and radiologists for anatomic evaluation of the tibiofibular syndesmosis area.

Comparison of radiologic and arthroscopic diagnoses of distal tibiofibular syndesmosis disruption in acute ankle fracture

PURPOSE

The purpose of this study was to compare intraoperative stress radiography and ankle arthroscopy in the evaluation of distal tibiofibular syndesmosis disruption in acute ankle fracture.

TYPE OF STUDY

Prospective study.

METHODS

We treated 53 Weber type B or C ankle fractures without radiographic evidence of frank syndesmosis diastasis. Intraoperative stress radiography and ankle arthroscopy were performed. Syndesmotic screws were inserted in those patients with syndesmosis diastasis. Screws were removed 12 weeks later and second-look ankle arthroscopy was performed at the same time.

RESULTS

Sixteen cases (30.2%) had positive intraoperative stress radiographs; 35 cases (66.0%) had positive arthroscopic findings of syndesmosis diastasis, including various combinations of coronal, sagittal, and rotational planes of instability. During second-look arthroscopy, 31 of 34 patients with syndesmotic screws showed healing of the syndesmotic ligaments and the syndesmosis became stable.

CONCLUSIONS

Ankle arthroscopy excels intraoperative stress radiography in detecting syndesmosis disruption. It also provides assessment of different planes of instability and assists anatomic reduction of the syndesmosis. Intraoperative radiography still does play an important role in assessing fracture reduction and proper restoration of fibular length and longitudinal orientation of the syndesmosis.

LEVEL OF EVIDENCE

Level 2.

Radiographic measurements do not predict syndesmotic injury in ankle fractures: an MRI study

Several radiographic measurements have been described and are used to determine ligamentous injury in ankle fractures, particularly of the deltoid and syndesmosis complex. Because the accuracy of these radiographic measurements has been questioned, we sought to evaluate their accuracy using magnetic resonance imaging as an indicator for injury. Seventy patients with closed ankle fractures were entered prospectively into the study, and all had standard plain radiographic evaluations before reduction (anteroposterior, lateral, and mortise) and magnetic resonance imaging. Four radiographic measurements were made on initial ankle injury films: tibiofibular clear space on the anteroposterior view, tibiofibular overlap on the anteroposterior and mortise views, and medial clear space on the mortise view. These radiographic measurements and their association with magnetic resonance imaging findings then were analyzed. A medial clear space measurement greater than 4 mm correlated with disruption of the deltoid and the tibiofibular ligaments. We found no association between the tibiofibular clear space and overlap measurements on radiographs with syndesmotic injury on magnetic resonance imaging scans.

LEVEL OF EVIDENCE

Prognostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Magnetic resonance arthrographic evaluation of syndesmotic diastasis in ankle fractures

INTRODUCTION

We examined whether magnetic resonance arthrography (MRA) contributes to the diagnosis of syndesmotic complex disruption in ankle fractures. Patients suffering syndesmotic diastasis according to conventional radiographic criteria were evaluated by MRI and MRA.

MATERIAL AND METHODS

Fifteen patients (15 ankles) with Denis-Weber type B and C fractures and were suspected of having syndesmotic diastasis considering tibiofibular clear space and tibiofibular overlap measurements in conventional radiographs were prospectively evaluated by MRI and MRA methods. Syndesmotic diastasis was diagnosed by radiographic, MRI, and MRA findings and by intraoperative observation and assessment criteria. Differences between MRI and MRA findings were tested statistically. Conventional radiography, MRI, and MRA results were analyzed by two independent observers, and interobserver concordance was also assessed.

RESULTS

In 15 patients regarded to have syndesmotic diastasis on conventional radiography the diagnosis was confirmed in 8 (53.3%) with MRI and 12 (80%) with MRA. Following overall assessment 13 of 15 patients (86.6%) were determined to have diastasis. There were statistically significant differences in diagnosis after MRI and after MRA. There was interobserver concordance in conventional radiographic, MRA assessments, and in assessments for anterior and posterior tibiofibular ligaments separately in MRI.

CONCLUSIONS

These results suggest that conventional radiography and MRI is not sufficient in assessing syndesmotic disruption, and that MRA can make an important contribution to diagnosis in ankle fractures.